The purpose of a blog should be primarily that of a diary. You show it to other people, and if you are like Samuel Pepys, some will even read it. For the most part however, blogs have become where the self-absorbed choose to spew out whatever ill-thought-out tripe that the blogger is thinking at that moment. The definition of a "good" blog is one that mostly agrees with your own ill-thought-out tripe.
The world is a complex place, but us bloggers usually take a small section out of it and grind their teeth on it like it was a piece of meat until it submits to their world-view. The trouble with this methodology is that once the process is complete, the subject, like a piece of meat so treated, is usually unfit for consumption by others
But now that I am getting to be an old man. As such, I have to be careful to keep myself from becoming politically and culturally myopic. Like the rest of the boomers, I was brought up to believe in the "truth" that the world cares about and values my opinion. That "truth" is becoming more and more transparently false every morning that I wake up and open my eyes.
The world has its own agenda, one that we do not form, but rather we swim in like fish in a sea. We are minnows in a sea where predators exist, and we try to convince ourselves that we can vote the predators into extinction. If we are not careful in our blogging, and in the blogs that we read, we will start to think that we are uniquely correct in our views and that the world agrees with us because we have found a string of folks who see things our way.
But the predators in our world are not democrats, and they don't listen to or even acknowledge the existence of these little schools of similar fish. They will swim away for a while, mostly because they are not hungry right then, but they will be back when it is time.